An X-ray CT apparatus is an apparatus which creates a cross-sectional image of a subject using X-rays. In one collection data, the width in the direction of the body axis of a round slice (image slice thickness) is as small as about 1 cm. Accordingly, in one normal imaging operation, data of a plurality of parts are collected while moving a subject in the body axis direction, and a plurality of images are created within a certain range. Depending on circumstances, the range is imaged a plurality of number of times while reciprocating the subject. A multi-slice X-ray CT apparatus comprises a plurality of rows of X-ray detectors in the body axis direction and can collect data of a plurality of parts at a time. A combination of detectors makes it possible to create a plurality of images with different image slice thicknesses by one data collection operation.
A conventional apparatus needs to perform a plurality of imaging operations in order to obtain images with a plurality of image slice thicknesses. In contrast with this, a multi-slice CT allows creation of images with a plurality of image slice thicknesses at a time and shortens the time required for one test. This makes it possible to increase the range of data collection in one test operation and increase the number of tests to be performed within a predetermined time, thus increasing the number of images to be stored in an image storage region.
When selecting a desired one from images stored in the image storage region to perform image analysis processing using a plurality of created images, pieces of image accompanying information which serve as pieces of character information accompanying the pieces of image data and reduced images created from the pieces of image data are displayed in a list. The operator manually selects an image from the list (see Japanese Patent Laid-Open No. 9-223155).
However, in the case of images with different image slice thicknesses obtained by one imaging operation, they are substantially equal in parameters other than image slice thickness, and thus, it is difficult to select a desired image from a list of pieces of image accompanying information. If a change in imaging position on the same subject is about 1 mm, it is more difficult to distinguish among reduced images with different imaging positions than among normal-sized images. As described above, since the number of images to be created tends to increase in a multi-slice CT, list display of all images and selection operation become complicated. An object of the present invention is to facilitate such complicated image selection.